Welcome to the crypto space and i don't see anything wrong in asking what you don't know. All coins in the crypto space are called cryptocurrencies but there is a difference though, BTC is the first cryptocurrency while all other coins are called Alternative cryptocurrencies or Alternative Coins hence the short form which is Altcoins. Therefore this is the only difference between ETH and BTC, although each have their own features which makes them stand out. Also, the Influential nature of an altcoin depends on the altcoin itself, that is, ETH is very influential when compared to others, owing to its features which contributed to its position on the coinmarketcap. On the other hand, most new altcoins are less influential and will either grow with time or die with time, which also depends on the team.